1Cook rice as directed on package.
2Meanwhile, cut chicken into 2x1/4-inch strips. Spray 12-inch nonstick skillet with cooking spray; heat over medium-high heat. Add chicken; sprinkle with pepper and garlic powder. Cook and stir 4 to 6 minutes or until brown. Add onion; cook and stir 2 minutes.
3Stir in frozen vegetables and water. Heat to boiling; reduce heat to medium. Cover and cook 5 to 7 minutes, stirring occasionally, until vegetables are tender.
4Mix stir-fry sauce and cornstarch until smooth; stir into mixture in skillet. Heat to boiling, stirring constantly. Boil and stir 1 minute. Divide rice among bowls. Top with chicken mixture.